Kidney disease is a common cause of illness in adult iguanas, although, any age animal can be affected. The signs of renal disease in the iguana may be vague and include decreased appetite with weight loss and weakness and at times muscle twitching or toe tremors as result of calcium imbalances. Dogs and cats with renal disease frequently drink excessively, but increased thirst is rarely seen in iguanas with this condition. Sometimes enlarged kidneys can be felt in the abdomen or at the base of the tail.

This seven year old male iguana is suffering from kidney failure.His appetite has been poor for over a month, resulting in weight loss and dehydration. He is now weak and depressed prompting the veterinarian to perform a blood analysis that is consistent with kidney disease.

Laboratory blood evaluation is important for diagnosing kidney disease. Kidney disease in iguanas usually results in changes in the blood calcium and phosphorus levels. Blood calcium levels tend to decrease below normal and the phosphorus levels become elevated. Uric acid, a byproduct of protein breakdown in reptiles, may or may not be elevated and is therefore an insensitive indicator of kidney disease in the green iguana. There must be very significant or specific injury to the iguana’s kidney to see a rise in uric acid. Blood abnormalities may also include elevated white blood cell counts and decreased numbers of red blood cells (anemia). Analysis of the urine is of limited use in iguanas to assess the kidneys. Biopsies of the kidneys are recommended to help with specific diagnosis and characterize the nature of the kidney disease. This information can help with prognosis and therapy.

The causes of this all-too-common problem are still speculative. The amount and type of protein in the diet are called into question. Remember that iguanas are herbivores and should receive a vegetarian diet of leafy greens. Supplements, especially calcium and vitamin D, are capable of producing or worsening kidney disease. It is wise to add supplements judiciously – more during growth and less in adulthood. Stress in captivity stemming from diet, temperature, lighting, exercise, and lack of social interaction or normal routines are all believed to cause increased levels of stress hormones, and decreased levels of immunity.

Water balance is now thought to be a major factor in the development of iguana renal disease. Chronic dehydration may be occurring in these reptiles, making the kidneys susceptible to injury. The iguana’s natural habitat is one of high relative humidity (central rain forest); therefore, a captive environmental humidity of around 50% is probably not adequate. We don’t know enough to say for sure but 75% - 85% humidity is likely better. Unless there is an elaborate enclosure with automatic misters, one should use a mist sprayer daily to moisten the iguana and its environment. Iguanas acquire much of their water from their food. This is why we recommend feeding fresh vegetable diets with water added and avoiding dry pelleted diets. The other factor is the manner in which iguanas drink water. Iguanas rarely if ever drink from water bowls or standing water. They will, however, drink if there is moving water and will lap up water droplets. This is another good reason to mist the cage daily.

Treatment of renal disease in iguanas is similar to other species. Fluid therapy is important to flush wastes and help normalize electrolyte abnormalities. Phosphorus binders and calcium supplements are often used. Antibiotics are sometimes needed if kidney infection is suspected or diagnosed with biopsies. Antinausea medications may help improve appetite, however, force feeding is often needed. Anabolic steroids may benefit some patients but is not commonly done. Unfortunately many iguanas with kidney disease are euthanized shortly after diagnosis due to a poor prognosis and quality of life.

Due to improved husbandry and care, the lifespan of the iguana has increased, and we now see many more older animals. On the one hand it is rewarding to see captive iguanas living longer, however with this positive, comes the downside of seeing more diseases associated with old age. Kidney disease is most likely the consequence of multiple factors and as our knowledge advances we hope to diminish its incidence. With greater awareness and diligent husbandry, our goal is to see future generations of iguanas thrive in their newfound role as our immediate companions.